Poke Radar
In all games that it appears in, the Poké Radar is obtained after receiving the National Pokédex. It can only be used in tall grass, while on foot. When used, a tune will begin to play, and up to four patches of grass will shake briefly. Upon entering one of these patches of grass, a battle with a wild Pokémon will begin immediately, even if the player is using a Repel. Depending on the game, different patches may shake in a different way, corresponding to rarer species of wild Pokémon. However, all games feature a very rare and distinct type of shaking grass that glows white twice; such a grass patch will always contain a Shiny Pokémon. Roaming Pokémon cannot be encountered while using the Poké Radar.needed Like the Vs. Seeker, the Radar's battery must be charged after use by walking around. It takes 50 steps to fully charge the Poké Radar. If the wild Pokémon is knocked out or captured in a Poké Ball, a chain will begin; this is the principle mechanic of the Poké Radar and crucial to increasing the probability of encountering a Shiny Pokémon. When a chain is in progress, the Poké Radar will automatically activate again at the end of the battle, causing up to four more grass patches to shake. Depending on various circumstances, one of these patches may be more likely to contain the same species of Pokémon as the one just encountered; defeating or catching such a Pokémon will continue to increase the chain by 1. If a wild Pokémon of a different species is encountered, or if a battle ends without defeating or capturing the wild Pokémon, or if a wild Pokémon is encountered outside of the Poké Radar, then the chain will break and the Poké Radar will not activate again at the end of the battle. A chain can also automatically break if the player uses the Bicycle or Roller Skates, if the player scrolls all shaking grass patches off-screen by moving too far away from them, or an Egg hatches. Activating the Poké Radar manually in the middle of a chain will not break the chain, and will simply generate up to four new patches of shaking grass, replacing the old ones. This action is known as "resetting" the Radar. It is commonly used when none of the four patches is deemed likely to continue the chain; this determination varies between games. As the chain length increases, the probability of finding a Shiny patch also increases, up to a certain maximum. After reaching this maximum, the player no longer needs to attempt to increase the chain, and can simply recharge and reset the Radar over and over until a Shiny patch appears. In Diamond, Pearl, and Platinum Bag Poké Radar Sprite.png The Poké Radar is obtained from Professor Rowan in his lab immediately after receiving the National Pokédex from Professor Oak; however, he will not explain how it works very thoroughly. In Pokémon Platinum, once the player receives an Eevee from Bebe in Hearthome Cityneeded, the player character of the opposite gender of the player (Dawn or Lucas) will give a more practical demonstration on Route 202. In these games only, the player can encounter certain Pokémon with the Poké Radar that would not be normally found on that route; these Pokémon are often not native to the Sinnoh regional Pokédex. For example, the Poké Radar is the only way to encounter a Nidoran♀ on Route 201. When the Poké Radar is used, the game generates four "rings" around the player, with the first ring consisting of the eight squares surrounding the player, the second ring consisting of the 16 squares surrounding the first ring, and so on for the third and fourth rings. One random square in each ring will be selected, and if that square is a patch of grass, that patch will shake. Therefore, the maximum number of patches that can shake with each use of the Poké Radar is four; if fewer than four patches shake, then one or more of the randomly selected squares were not patches of grass. If all four squares did not contain grass, then the game will display the message "The grassy patch remained silent..." and the chain will automatically break. The patch in the farthest "ring" is the most likely to continue a chain. Different formations of grass patches indicate different likelihoods of continuing a chain. If a swarm ends while a chain is in progress, or a Pokémon otherwise ceases to become available, then that Pokémon will continue to be available until the chain is broken. The probability of encountering a Shiny Pokémon becomes maximized at a chain length of 40, at approximately 1/200. This is a substantial increase from the usual probability of 1/8192. Since up to four patches of grass appear each time the Poké Radar is used, and each has an independent 1/200 chance, the overall probability of finding at least one Shiny patch for each reset of the Poké Radar is about 1/50. It is possible, although very unlikely, for multiple Shiny patches to appear on one reset. Entering a Shiny patch will never break a chain. One of the many functions of the Pokétch is to display the current chain and the three best chains made so far. Shiny Probability The formula for the probability of finding a Shiny Pokémon. nc is the number of Pokémon in the chain, up to 40. Based on the formula depicted at right, the probability of encountering a Shiny Pokémon can be approximated as 1/8000 for a chain of 1, 1/7800 for a chain of 2, 1/7600 for a chain of 3, and so on up to 1/200 for a chain of 40. Note that it takes a while for a chain to start paying off - the probability does not exceed that of the Masuda method until a chain length of 33. After that point, the probabilities start to increase very strongly, with a chain of 40 having double the probability (1/200) compared to a chain of 39 (1/400). As all Pokémon games prior to Generation V perform calculations strictly with integers, there exist some roundoff errors in the probability determination (as noted by the ceiling function in the formula). A game-accurate list of probabilities for each chain is as follows: Chain length Shiny Probability 0* 8/65536 (1/8192)* 1 9/65536 (~1/7282) 2 9/65536 (~1/7282) 3 9/65536 (~1/7282) 4 9/65536 (~1/7282) 5 10/65536 (~1/6554) 6 10/65536 (~1/6554) 7 10/65536 (~1/6554) 8 10/65536 (~1/6554) 9 11/65536 (~1/5958) 10 11/65536 (~1/5958) 11 11/65536 (~1/5958) 12 12/65536 (~1/5461) 13 12/65536 (~1/5461) 14 13/65536 (~1/5041) 15 13/65536 (~1/5041) 16 14/65536 (~1/4681) 17 14/65536 (~1/4681) 18 15/65536 (~1/4369) 19 15/65536 (~1/4369) 20 16/65536 (1/4096) 21 17/65536 (~1/3855) 22 18/65536 (~1/3641) 23 19/65536 (~1/3449) 24 20/65536 (~1/3277) 25 21/65536 (~1/3121) 26 22/65536 (~1/2979) 27 24/65536 (~1/2731) 28 26/65536 (~1/2521) 29 28/65536 (~1/2341) 30 30/65536 (~1/2185) 31 33/65536 (~1/1986) 32 37/65536 (~1/1771) 33 41/65536 (~1/1598) 34 47/65536 (~1/1394) 35 55/65536 (~1/1192) 36 66/65536 (~1/993) 37 82/65536 (~1/799) 38 110/65536 (~1/596) 39 164/65536 (~1/400) 40+ 328/65536 (~1/200) *A Shiny patch cannot appear on a chain length of 0, but all non-Shiny patches still have the usual 1/8192 chance of encountering a Shiny Pokémon. ...Information from http://bulbapedia.bulbagarden.net/wiki/Pok%C3%A9_Radar